The present invention relates to devices used in electromagnetic treatment of living tissue such as bone. It has been known for some time that certain electrical and magnetic signals can have a therapeutic effect in treatment of living tissue, and such treatment is generally known as electro-osteogenesis.
The use of electrical and electromagnetic signals in stimulating repair and growth of living tissue such as bones has been known for some time in both humans and animals. In one technique of this type electrodes are actually implanted in the tissue to be treated. An alternative technique involves the application of an electromagnetic field to the affected area via an external device such as a coil or solenoid which is secured to the body part or to a plaster cast surrounding the affected body part. The latter technique is normally more suitable since it does not require surgical invasion of the treatment site.
The problems involved in use of an external device are in accurately positioning it at a body site adjacent the internal tissue area to be treated, securing it in place so that it is reasonably comfortable and unlikely to become dislodged while allowing the subject undergoing treatment to move relatively freely, and ensuring that the required uniform field is produced. Up to now such placement has normally been done in a doctor's office or surgery, with the subject sometimes being required to stay relatively immobile while treatment is in progress.
U.S. Pat. No. 3,915,151 of Kraus shows one technique in which a coil is provided in a tubular member which can be slid over an extremity such as a leg. The coil is of rigid construction and will therefore not conform to the external shape of the leg.
The problem with encircling a body part such as an arm, leg, or torso with a rigid solenoid coil device is that the device must be large enough to slip over a relatively larger diameter body part, e.g. a hand, foot or head and shoulders, in which case it will be significantly larger than the body part it encircles when it arrives at the correct site. This results in a power consumption which is significantly larger than necessary, because the rigid construction of the coil requires that it be larger in diameter than that of the underlying body part, and the power required is proportional to d.sup.3 where d represents the diameter of a basic air-core coil, e.g. a ring, solenoid, Helmholtz or similar coils.